Process of making metallic filaments.



K. FARKAS PROCESS OF MAKING METALLIC FILAMENTS;

APPLICATION FILED DEC- I3, 1910- 1 ,1 8,57, Patented June 20, 1916.-

UNTTED PATENT QFFTQE.

KARL FARKAS, F GLEN RIDGE, NEW JERSEY, ASSIGNOR TO J. EMIL WEEHAWKEN, NEW JERSEY.

PROCESS OF MAKING METALLIC IEILAMENTS.

- Specification of Letters Iatent.

Patented June 20, 1916.

Application filed. December 13, 1910. Serial No. 597,140.

- dent of Glen Ttidge, county of Essex, and

State of New Jersey, have invented certain new and useful Improvements in the Process of Malring Metallic Filaments, of which the following is a specification.

This invention has reference to flexible metallic-filaments and the process of producing same.

Metallic filaments are usually produced by mixing refractory oxids such as for instance tungsten oxid, with glutinous carbonaceous-material that acts as a binder. The carefully prepared ,uniform mass is then pressed through a die by exceedingly high pressure, in some instances hydrauhc pressure is used and a filament heated by the electric current in'an evacuated chamber in the presence of hydrogen. This process as generally outlined above, produces metallic filaments that arebrittl'e and verydelicate. They are so fragile that they have to be handled with the greatest of care during the manufacture of the lamp and may be broken like fine steei wires. The cause of this extreme fragility of metallic filaments-is that it is very difficult to produce filaments which are free fromimpurities. Traces of foreign metallic oxide or metals or carbonaceous matter and probably carbids formed'by the carbon and metal-may be found therein and the result is, as above stated a very delicate and fragile filament l, which is brittle and cannotbe bent except.

after pressing when the glutinous binder is.- still therein. The filament which has been reduced by hydrogen and is then in the so-ealled metallic state of. course. softens when electrically heated while inan exhausted glass receiver or in a finishedlampbut this property of the filament at that condition cannot be utilized for shaping filaments for .practical purposes.

It is the object of the present invention to produce metallic filaments which are flexible before they are inserted into a lamp when they are already in the metallic state so that same may be shaped into a desired form to such an extent that other than the present shapes of. filaments..may be made therefrom. It is self-evident that with such metallic filaments a great saving is effected because the breakage during the manufacture of lamps is reduced to a minimum.

In carrying the present invention into effect the refractory o'xids are first purified by transforming them into the higheststage of oxidation and after these have been carefully prepared the plastic mass is formed, the filament pressed and the pressed filament is treated in an electric oven wherein it is reduced. This oven is represented in the accompanying drawing in which:

Figure 1 represents in elevation an apparatus for pressing metallic filaments and an electric oven in which they are reduced. Fig. 2 represents in vertical section the electric oven which embodies in desirable form the present improvements.

Similar characters of reference denote like parts in all the figures.

As above stated the refractory oxids, for instance tungsten oxids are first purified by WALSCHEID, OF

transforming them intov the highest state of oxidation. This is accomplished by heating them in anatmosphere of oxygen purpose of producing the highest are,'f or instance, transformed into tungsten trioxld'WO which is yellow and if for the urposeofpurification the hydrate was burning out impurities. By this ormed for instance WO,H the treatment a with oxygen serves a further purification. In the described purified tungstic oxids none of the brown tungstous oxids are found any -more. The purified tungstic oxids are now through. silk sieves so as to separate out only the very finest impalpable powder. This very fine impalpable powder is now passed through tight rollers of the kind the impalp'ah le powder of the oxid is, mixed with about 2 gr. of the binder. When a homogeneous mass has been obtained same is placed into the filament press a, shown in Fig. 1, from which the filament 2) issues and I passes into the electric oven 0. The filaments are pressed very slowly so that at the best ten inches of filament are produced per minute.

The electric oven through which the filament passes is shown in section, in Fig. 2. The oven consists of an inner porcelain tube 61 shown in elevation. Around this porcelain tube nickel wire "a is wound at. such distance that it is insulated by the porcelain of which the tube is composed; In this way this inner porcelain tube (1 may be electrically heated. This tube is open. A second porcelain tube t surrounds the tube 03. This -tube is closed at the top and bottom except to note that a pipe 7 leads into same for the purpose of introducing a gas into same. The second porcelain tube is surrounded by nickel wire 9 or the like so that same may be electrically heated. Both tubes-are inclosed into a steel shell 72, and the space between the layer of wire 9 and the walls of the steel or iron shell is filled with asbestos i. The surrounding shell h is so constructed that it closes the porcelain tube It but leaves the tube (2 open. Centrally at the top of the shell it there is a conducting roller j and at.

the bottom a like roller 70 on which the filament Z) is conducted through the oven and by means of these conducting rollers j and k the filament may be electrically heated while it passes through the oven. When starting to make filaments hydrogen gas is continuously passed through the inner porcelain tube (Z from below whereby first of all the air is expelled.' The space within the porcelain tube t is also filled with hy drogen gas through the tube f and sufficient I gas is passed through to expel the air a pure organic binder. When entering the porcelain tube d the filament is reduced by the heated hydrogen and after passing the lower conductive roller 7c the filament itself is electrically heated whereby a complete reduction to pure metal takes place. By the heated hydrogen and by heating the filament electrically all oxids are reduced and all organic matter from the binder is completely burned out. Simultaneously the inclosed hydrogen atmosphere in the tube t is heated by the hot porcelain tubes and thus aids in the production of a terrific heat within the electric oven. The filament when leaving the roller is is now wound on suitable rolls and is flexible like metallic wire and may be formed into various shapes of filaments. In fact it is pure metallic wire after the treatment in the electric oven and may be handled as such and drawn out into still finer wire if desired.

I claim as my invention:

1. The process of producing flexible metallic filaments for incandescent electric lamps consisting in passing successively and continuously each port on of the pressed filament, while said portion is rendered incandescent, through a continuously flowing current of heated hydrogen surrounded by a heated stationary atmosphere of hydrogen, whereby the filament is reduced to a pure metallic state.

2. The process of producing flexible tungsten filaments for metallic filament lamps consisting in passing successively and contin uously each portion of the pressed filament, while said portion is rendered incandescent, through a continuously flowing current'of heated hydrogen surrounded by a heated stationary atmosphere of hydrogen, whereby the filament is reduced to a pure metallic state.

3. The process of producing flexible metallic filaments for incandescent electric lamps consisting in pressing continuously a filamentary thread and passing successively and continuously each portion of the pressed filament, while said portion is rendered incandescent, through a continuously flowing current of heated hydrogen surrounded by a heated stationary atmosphere of hydrogen, whereby the filament is reduced to a pure metallic state. i

4:. The process of-producing flexible tung-- sten filaments for metallic filament lamps consisting "in pressing continuously a filamentary'thread and passing said thread directly, portion by portion, while each portion is rendered incandescent, through a continuously flowing current of heated hydrogen surrounded by a heated stationary atmosphere of hydrogen, whereby the filamentary thread is reduced to a pure metallic state, and then shaping filaments therefrom.

5. The process of producing flexible metallicfilaments for incandescent electric lamps consisting in passing successively each portion of the pressed filament composed of highly r fractory oxids while being rendered incandescent through a continu- 6. The process of producing flexible tungsten filaments for metallic filarnerrt lamps thereby to pure tungsten wire which is flexieonsisting in passing successively each p0rtion of the pressed filament through a continuously flowing current of heated hydro- While being rendered incandescent therein, said current of heated hydrogen being surrounded by a heated stationary atmosphere of hydrogenreducing the filament of December, 1910.

e before being placed in the lamp. 10

Signed at NewYork, N. Y., this 12th day KARL FARKAS. Witnesses CORINNE MYERS, VERA PAULsEN.

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